Duct rodding machine



C. JASPER Er AL DUCT RODDING MACHINE March 25, 1952 6 Sheets-Sheet 1 Filed March 17, 1950 INVENTORS C forye Jasper/ BY .Geo/ge T Haw/a,

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March 25, 1952 C, JASPER 1-AL DUCT RODDING MACHINE 6 Sheets-Sheet 2 Filed March 17, 1950 @l ,www

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DUCT RODDING MACHINE Filed March 17., 1950 6 Sheets-Sheet 3 /ml wunll'/ 7 INVENToR Cron e Jef; l

A BY ofge T11/awk. M W1, mi @I C. JASPER ET AL March 25, 1952 DUCT RODDING MACHINE '6 sheets-sheet 4 Filed March 17, 1950 @QQEQ March 25; 1952 c. JASPER E-r Al.

DUCT RODDING MACHINE 6 Sheets-Sheet 5 Filed Mar'Ch 17, 1950 INVENToR. korg/e, Jas/jef? BY 6fm/ge Z" Haw/,

m @MVM c. JASPER Er AL 2,590,414

DUCT RODDING MACHINE Sheets-Sheet 6 March 25, 1952 Filed March 17, l9 50 Patented Mar. 25, 1952 DUCT RODDING MACHINE CronjeJasper, Villa Park, and George T. Hawk, Chicago, Ill.

Application March '17, 1950, Serial No. 150,182

(Cl. F15-378) 18. Claims. l

.Our invention relates to the vclass of cable laying devices and, more specincally, is 4concerned with duct rodding machines for laying cable in ducts or conduits.

Duct rodding machines `for threading cable in underground ducts kor conduits are known, and we do not claim the same broadly.

Our improvements are concerned with the type of duct rodding machine in which fluid under pressure is utilized for eiiecting stepwise movement of the latter in a duct. An example of this type of duct rodding machine is disclosed in our copending application, Serial No. 787,252, led November 20, 1947, now APatent No. 2,518,330.

According to our invention, we provide a main fluid motor unit comprising a cylinder to which is flexibly mounted at the forward end thereof a fluid operated front duct gripping unit and a piston to which is flexibly connected at the rear end thereof a uid operated rear duct gripping unit. Both the front and rear duct gripping units have auxiliary fluid motors associated therewith for controlling gripping of the duct gripping units. The main fluid motor expands and contracts the assembly to effect a pawl and ratchet-like step progression of the entire device in the duct in which it operates.

One of the features of our present invention V is the provision of a pair of vertically extending cam members, one pivotally mounted to each of the front andrear duct gripping vunits about an axis extending transversely thereof. When the cam members are rotated into engagement with the upper surface of the duct by means of the yauxiliary fluid motors, the duct is securely gripped at the upper surface by the cam members and at the lower surface by the frame members of the 'front and rear duct gripping units.

Another feature of our invention is the unique manner in which the aforedescribed lcam members are mounted in order that the cam members may be released quickly and positively from engagement with the duct without binding with the upper surface of the latter. The quick release of the cam members is eiected by the provision of a first inclined longitudinal lost motion connection between the lower end of each of the cam members and the adjacent frames of the front and rear duct gripping units, and a second transverse lost motion connection between the intermediate portions of each of the cams and the associated parts of the auxiliary motors. The lost motion connections permit V2 the cam members -todrop away from ythe upper surface of the duct upon initial -release movement by the auxiliary motors.

Another feature of our invention is the ,provision of dash `pot members one adjacenteach end of the cylinder of Athe main fluid motor unit for absorbing shock reactions of the main piston at the end of its forward and reverse stroke.

Still another feature of `our invention is the disposal Vof the valve mechanism, `for controlling fluid ow to the front andy rear `duct gripping units and the main fluid motor unit, within the piston of the latter, thereby conserving space and eliminating external uid connections gbetween the valve mechanism and the cylinder of the main uid motor unit.

The valve mechanism comprises -a valve .block having suitable fluid passageways -formed therein which are placed in communication with the 'front and rear duct gripping .units andthe main fluid motor-unit. Disposed .withina cavity formed in the `valve block ris a rectilinearlymovable main valve for effecting connection between the desired uidpassagewaysand afsource of fluid under pressure. Also disposed within a cavity formed in the valve block is a Vrectilinearly `movable pilot valve for Aadmitting fiuid under pressure toopposite ends of themain valve for effecting Arectilinear shifting of the latter. The pilot valve has reduced end .portions that protrude outwardly at the ends ofthe main piston and are adapted .to strike the dash pot members at the ends lof the main cylinder when the main piston is at the end of its .forward or reverse stroke. When one -of the ends of the pilot valve strikes a dash Ypot member, the pilot valve is shifted to the opposite .end of the cavity in which it is carried.

A feature of our valve mechanism is `that by using a pilot -valve to control movement of the main valve, the latter 4will not become stopped in an intermediate position because only 4full fluid pressure is admitted to the main valve by the pilot valve.

Another feature of our valve mechanism is the formation of spaced annular grooveswin the peripheral walls of the vcavities within which the main and :pilot valves are disposed. These grooves have been :provided so that the iiuid under pressure nowing through the valve .may exert an equal force around the periphery -of the valves, thereby eliminati-ng binding -of the latter within the cavities.

Now, in order to acquaint those skilled `in the 3 art with the manner of constructing and using the device of our present invention in accordance with the principles set forth herein, we shall describe in connection with the accompanying drawings a preferred embodiment of our invention.

In the drawings:

Figures 1 and la, together, show a plan view of the duct rodding machine of our present invention;

Figures 2 and 2a, together, show a vertical sectional view of the duct rodding machine of our invention taken along the line 2 2 in Figures 1 and la, looking in the direction indicated by the arrows;

Figure 3 is a side elevational view of the cylinder of the main fluid motor unit of the duct rodding machine of Figures 1 and la;

Figure 4 is a vertical sectional view of the cylinder of Figure 3 taken along the line 4 4, looking in the direction indicated by the arrows;

Figure 5 is an end View of the valve block which comprises the piston of the main fluid motor unit of the duct rodding machine of Figure 1;

Figure 6 is an end view of the valve block which has been rotated about its longitudinally extending central axis from the position shown in Figure 5;

Figure '7 is a lengthwise vertical sectional view of the valve block taken along the line 1-1 in Figure 6, looking in the direction indicated by the arrows;

Figure 8 is an end view of the valve block which has been rotated about its longitudinally extending central axis from the position shown in Figure 5;

Figure 9 is a lengthwise vertical sectional view of the valve block taken along the line 9-9 in Figure 8, looking in the direction indicated by the arrows;

Figure 10 is an end view of the valve block taken along the line IU-I in Figure 9, looking in the direction indicated by the arrows;

Figure ll is a vertical transverse sectional View ofthe valve block taken along the line H-Il in Figure '7, looking in the direction indicated by the arrows;

`Figure 12 is a vertical transverse sectional view of the valve block taken along the line |2--I2 in Figure 7, looking in the direction indicated by the arrows;

Figure 13 is a lengthwise sectional view of the valve block taken along the line |3|3 in Figure 5, looking in the direction indicated by the arrows;

Figure 14 is a vertical transverse sectional view of the valve block taken along the line Ill-I4 in Figure 7, looking in the direction indicated by the arrows;

Figure 15 is an end view of the valve block which has been rotated about its longitudinally extending central axis from the position shown in Figure 5;

Figure 16 is a lengthwise sectional view of the valve block taken along the line Iii-I6 in Figure l5, looking in the direction indicated by the arrows;

Figure 17 is a vertical transverse sectional view of the valve block taken along the line l'I-ll in Figure '7, looking in the direction indicated by the arrows;

Figure 18 'is a vertical transverse sectional view of the valve block taken along the line I8-IB in Figurel f7, looking in the direction indicated by the arrows;

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Figure 19 is an end view of a plate member which is secured to the one end of the valve block;

Figure 20 is a horizontal sectional view of the end member shown in Figure 19 taken along the line 2li-20 in Figure 19, looking in the direction indicated by the arrows;

Figure 21 is an end view of an end block which is secured to the opposite end of the valve block as is the plate member shown in Figures 19 and 20;

Figure 22 is a horizontal sectional view of the end block shown in Figure 21 taken along the line 22-22 in Figure 2l, looking in the direction indicated by the arrows;

Figure 23 is an end view of the valve block which has been rotated about its longitudinally extending central axis from the position shown in Figure 5;

Figure 24 is a lengthwise sectional view of the valve block taken along the line 2li- 24 in Figure 23, looking in the direction indicated by the arrows;

Figure 25 is a schematic diagram of the uid passageways formed in the valve block showing the valves in one of their positions; and

Figure 26 is a schematic diagram of the iiuid passageways formed in the valve block showing the valves in the other of their positions.

Referring now to Figures l, la, 2, and 2a, there is indicated generally by the reference numeral 23 the duct rodding machine of our present invention which is particularly adapted for threading cable in underground ducts or conduits provided for housing cables or conductors.

The duct rodding machine 2i] comprises a front duct gripping unit 2l, a rear duct gripping unit 22, and an intermediate main fluid motor unit 23. The front and rear duct gripping units 2l and 22 are flexibly connected to the main motor unit 23 at the front and rear ends, respectively. With this arrangement, the duct rodding machine 23 is able to negotiate curves and pass over foreign matter, such as dirt or sand, which may collect in the duct or conduit.

The front duct gripping unit 2| comprises a frame member 23 having an upper transverse channel formed intermediate of the ends thereof. Suitably secured to the periphery of the rear vertical wall of the frame member 24, as by bolts 25, is a rearwardly extending cylinder 26 which has a circular plate or plug 2l secured in the rear end thereof, as by welding or equivalent means. Formed in the rear face of plug 21 are circumferentially spaced apart semispherical sockets, numbering three in the specific embodiment shown, which are adapted to receive the ball-shaped ends of parallel tie rods 28, 29, and 33. The ball-shaped ends of the tie rods 28, 29, and 36 are held within the semispherical sockets formed in the plug 2'! by means of a circular cap member 3! which has circumferentially spaced apart openings 3|, 32, and 35 therethrough, through which the central portions of the tie rods 2S, 29, and 33 are adapted to extend. The peripheral segments of the inner ends of the openings 3l, 32, and 35 are spherically formed to conform to the shape of the ends of the tie rods 23, 29, and 36. The cap member 30 is secured, as by bolts 31, or is otherwise detachably mounted to the rear surface of the plug 2. A central opening 33 is formed in the cap member 3U, and a central threaded opening 34 is formed in the plug 21 which is of a smaller diameter than the openingin the cap member 30. The purpose of the openings 33 and 34 will be fully described hereinafter.

Journaled in an opening in the front vertical wall vof the frame member 24 is the one end of a longitudinally extending piston rod 38 which, at itsfother end, extends through an opening in the rear vertical wall of the frame member 24 into the cylinder '26. Disposed within the cylinder 26 is a `piston assembly, indicated by the reference numeral 39, which is mounted to the rear end of the piston rod 38 by means of a nut 40. The piston assembly 39 comprises a circular disk member 4l, a circular seal 42, preferably made of leather, and a spring expander 43 for biasing the peripheral flange of the seal 42 into contact ,with the inner peripheral surface of the cylinder 26. rlhe piston assembly 39 is adapted for reciprocatory motion within the cylinder 26. A cylindrical helical spring 44, of rectangular cross section, is disposed concentrically about the piston rod 38 between the rear vertical wall of the Vframe member 24 and the circular disk 4l of the piston assembly 39 for normally biasing the latter, and the piston rod 35, toward the rear end of the cylinder 26. The cylinder and the piston assembly 39 form a first auxiliary fluid motor unit.

Disposed over the piston rod 33 between the front and rear vertical walls of the frame member v24, within the channel extending transversely thereof, is a vertically extending clevislike cam member 45 having angularly downwardly extending spaced apart arm portions 43 and 41. Formed intermediately of each of the arm portions 45 and 4l is a slot 4S. A horizontal pin 49 is inserted through a transverse opening in the-piston rod 33 and the ends of pin 49 are adapted to extend into the slots 48 in the arm portions 4B and 4l of the cam member 45. Formed adjacent the outer ends of the arm portions 46 and 4l are slots 45 which extend diagonally with respect to the slots 43. Disposed through the slots 5I is a transverse pin member 52 which is mounted at its ends in horizontally'spaced vertical ribs 53 and 54 of the frame member 24. The upper edge of the cam member 45 follows an arc of a circle which is eccentric -to a circle having a center that coincides with the pivot point defined by the pin member 52. The upper edge of the cam member 45 is formed eccentrically so that the angle between the perpendicular and the contact point of the cam edge and a duct is the same, irrespective of the diameter of the duct (within the range of diameters 'for which the duct rodding machine has been designed).

When the duct gripping unit 2i is placed in a duct or conduit, and fluid under pressure is admitted to the cylinder 25 through the opening 34 'in the plug member 2l, the piston assembly 39 and piston rod 38 are forced to the left, as viewed in Figures 1 and 2. Initial movement of the piston rod 38 to the left positions the pins 49 and 52 at the upper and lower ends of the slots 48 and 5|, respectively. Further movement of the piston rod to the left causes the ends of pin 49 to slide along the slots 48, forcing the cam member to rotate counterclockwise about pin 52. Counterclockwise rotation of cam member 45 urges the upper arcuate edges thereof into engagement with the adjacent upper peripheral wall portion -of the duct, thereby lforcing the vlower cylindrical segment of 6, theframe member 24 againstthe Iadjacent `lower peripheral portion of the duct.

Release of the duct gripping Vunit 2l is effected by bleeding the fluid pressure from the cylinder 23. Upon bleeding of the fluid pressure, the force of spring 44 moves the piston assembly 39 and piston rod 38 to the rightVas viewed in Figures 1 and 2. Initial'movement to the rghtof 'the piston rod 38 causes the slots `4t and '5| 'torslide downwardly about the pins 49 and 52, thereby permitting the arcuate edge of the cam member 45 to drop away from the-adjacent upper peripheral wall portion ofthe duct. With the provision of slots48 and 57|, and pins 49 and 52, release of Acam member 45 is quick and positive, rthus eliminating binding between the upper arcuate edge of the cam member 45 and the adjacent peripheral wall portion of the duct.

The rear duct gripping unit 22 issimilar `in construction, in many respects, tothe front duct gripping unit 2 I. The unit 22 comprises a frame member 65 having an upper transverse channel formed intermediate of the ends thereof. Suitably formed in the rear portion of the hub member 55 is a horizontal cylindrical opening or chamber 5|' which has a circular plate or plug 62 secured in the rear end thereof, as by welding or equivalent means. Mounted to the rear vertical surfaces of the plug 62 and frame member 60, as by circumferentially spaced bolts 63, is acap member 54 having an internal fluid passageway 65 which is adapted to make connection with a fluid passageway 65, formed lengthwise in the frame member 65 adjacent one side thereof, as viewed in Figures 2 and 2a, when the cap member 64 is in mounted position. The fluid passageway 65 opens outwardly centrally of the rear vertical surface of the cap member 64 and is threaded thereat to receive one end of a iluid pressure line or hose 5l which is connected at its other end to a source of fluid under pressure.

A circular seal 61, preferably of leather,-is disposed within the chamber 5l in the frame member 60 and is secured to the inner face of the plug 62 by means of a bolt 58 having threaded engagement with a central opening formed in the plug 62. The bolt 68 is also utilized for the mounting of a spring expander 69 which biases the peripheral flange of the seal 61 into contact with the adjacent inner peripheral wall of the chamber 6|.

Journaled in an opening in the front vertical wall of the frame member 55 is the one end of a longitudinally extending piston rod 14 which, at its other end, extends through an opening in the front vertical wall dening chamber 6l. Mounted to the end of the piston rod 14, within the chamber 6|, is a piston assembly, indicated at 15. The piston assembly l5 comprises a circular disk member 76, a circular seal 11, preferably of leather, and a spring expander 18 forl biasing the peripheral fiange of the seal 1'! into contact with the adjacent inner peripheral surface of the cylindrical wall of the chamber 6|. The piston assembly 'l5 is secured to the end of the piston rod 14 by means of a nut 15. A conical helical spring 80, of circular cross section, is disposed concentrically about the piston rod 14 between the front vertical wall of chamber 5I and the `circular disk i6 of the piston assembly 'l5 for urging the latter and the piston rod 'I4 toward the rear end of the chamber 6I. The chamber 5| and the piston assembly 'l5 form a second auxiliary fluid motor unit.

Disposed over the piston rod i4, within -the channel .extending transversely of the frame member 68, is a vertically extending clevis-like cam member 8|, like the cam member 45 associated with the front duct gripping unit 2 The cam member 8| has downwardly extending spaced apart arm portions 82 and 83 which have slots 84 formed intermediately thereof. A horizontal pin 85 is inserted through a transverse opening in the piston rod 14 and the ends of pin 85 are adapted to be received by the slots 84 in the arm portions 82 and 83 of the cam member 8|. Formed adjacent the outer ends of the arm portions 82 and 83 are slots 88 which extend diagonally with respect to the slots 84. Disposed through the slots 88 is a transverse pin 81 which is mounted at its ends in horizontally spaced apart vertical ribs 88 and 89 of the hub member 88. The upper edge of the cam member 8| is formed eccentrically for the same reasons as the afore-described cam member 45.

The operation of the rear duct gripping unit 22 is the same as the operation of the front duct gripping unit 2 l. That is, when fluid is admitted under pressure to the chamber 8|, the piston assembly 15 and piston rod 18 are forced to rthe left, as viewed in Figures 1, 1a, 2, and 2a. Initial movement of the piston rod 14 to the left positions the pins 85 and 81 at the upper and lower ends of the slots 84 and 86, respectively. Further movement of the piston rod 14 to the left causes the ends of the pin 85 to slide along the slot 84, forcing the cam member 8| to rotate counterclockwise about pin 81. If the rear duct gripping unit 22 is placed within a duct or conduit, counterclockwise rotation of cam member 8| urges the upper arcuate edges thereof into engagement with the adjacent upper peripheral portion of the duct, thereby forcing the lower cylindrical segment of the hub member 88 against the lower portion of the duct.

Release of the duct gripping unit 22 is effected by bleeding the fluid pressure from the chamber` 6| which permits the spring 88 to expand. Expansion of spring 88 moves the piston assembly 15 and piston rod 14 to the right, as viewed in Figures l, la, 2 and 2a. Initial movement to the right of the piston rod 'Us causes the slots S4 and 86 to slide downwardly about the pins 85 and 81, thereby permitting the arcuate upper edge of the cam member 8| to drop away from the adjacent upper peripheral wall portion of the duct. With the provision of slots 8-1 and 86, and pins 85 and 81, the release of cam member 8|, like the release of the cam member 85, is quick and positive, thus eliminating binding between the upper arcuate edge of the cam member 8| and the adjacent upper peripheral wall portion of the duct.

`The main fluid motor unit, indicated generally at 23, which is disposed between the front duct gripping unit 2| and the rear duct gripping unit 22, comprises a master cylinder unit 95 flexibly connected to the rear end of the front duct gripping unit 2| and a master piston assembly, indicated at 96, flexibly connected to the front end of the rear duct gripping unit 22.

' The master cylinder unit 95 comprises a cylinder 91 having a longitudinally extending groove 98 formed in the outer peripheral surface thereof, oiset to one side of a vertical plane passing through the axis of the cylinder 91, as best shown in Figures 3 and 4. An arcuate plate member 99 is suitably secured, as by welding, to the outer peripheral surface of the cylinder 91. Formed along the inner peripheral surface of the arcuate plate member 99 is a lengthwise extending groove |88 which is adapted to mate with the groove 98 in the cylinder 91. When the arcuate plate member 99 is in assembled position, the grooves 98 and. |08 define a uid passageway |8| extending longitudinally of the master cylinder unit 95. The fluid passageway |8| opens at its one end into the cylinder 91 adjacent the rear end thereof. A circular end member |82 is suitably secured, as by Welding, in the forward end of the cylinder 91. The end member |82 has a radially directed iiuid passageway |83 formed internally therein which, at its outer end, is adapted to connect with the forward end of the fluid passageway |8| and at its inner end is adapted to open outwardly centrally of the end member |82.

Threaded into the central opening of the end member |82 and extending forwardly therefrom, as shown in Figures 1, la, 2 and 2a, is a pipe stud |81 having an annular bead portion formed adjacent its outer end. Threaded into the central opening in the plug member 21 and extending through the central opening 33 in the cap member 38 of the front duct gripping unit 2| is a pipe stud member |88 which is similar in form to the pipe stud |81. Interconnecting the-outer ends of each of the stud members |81 and |88 is a sleeve member |89 which is maintained in position by means of a pair of spaced annular ring members ||8 and which are disposed coaxially about the periphery of the sleeve member |89, inwardly of the shoulder portions formed by the annular beads adjacent the outer ends of the pipe studs |81 and |88, respectively. A uid connection is thus effected between the rear end of the main cylinder unit 95 of the main fluid motor unit 28 and the cylinder 26 of the front duct gripping unit 2| through fluid passageway |8| extending longitudinally of the cylinder 91, fluid passageway |83 extending radially in the end member |82, pipe stud |81, exible sleeve member |89, and pipe stud |88.

In the outwardly facing surface of the end member |82 are a number of semispherical sockets which number three in the specic embodiment illustrated herein. These sockets are adapted to receive the enlarged ball-shaped ends of the tie rods 28, 29, and 36 which extend rearwardly from the front duct gripping unit 2|. The ball-shaped ends of the tie rods 28, 29, and 38 are adapted to be held within the semispherical sockets of end member |82 by means of a capmember having circumferentially spaced openings therethrough, through which the central portions of the tie rods 28, 29, and 38 are adapted to extend. The inner ends of the openings in the cap member |85 are semispherical segments, thus corresponding to the shape of the ends of the tie rods 28, 29, and 36. The cap member |85 has a central opening through which pipe stud |81 extends and is secured to the end member |82 by means of circumferentially spaced bolts |85. In order to facilitate the assembly of the cap members 38 and |85 about the tie rods 28, 29, and 36, the latter are fabricated in two parts and then welded together after the reduced ends of the parts have been inserted through the openings in the cap members 38 and |85.

From the foregoing description, it will be apparent that the front end of the master cylinder unit is flexibly connected through the tie rods 28, 29, and 36 to the rear end of the front' duct gripping unit 2|. That is, since the tie which permits limited relative movement, and since the otherv ends of the tie rods 28, 29, and 36 are similarly connected to the forward end of the master cylinder unit 95 in a manner permitting limited relative movement, this construction, in effect, permits limited relative lateral movement between the master cylinder unit 95 and the front duct gripping unit 2|.

The main piston assembly 96 disposed within the cylinder 91 of the main fluid motor unit 23 comprises-a valve block I I2, the detailsof which will be described more fully hereinafter. Secured to the rear end of the valve block |I2 by means of a plurality of circumferentially spaced bolts ||3 is an end block ||4 having a central opening formed therein which is partially threaded for receiving the threaded end of a tubular` piston rod ||5 extending rearwardly therefrom. The tubular piston rod ||5 is journaled intermediate of its end in a bushing member ||6 threaded into a central opening formed in a cap member ||1 which, in turn, is threaded into the end of the cylinder 91 of the main cylinder unit 95. The bushing member ||6 is held within the capmember ||1 by means of a lock ring IIS. Seal members I I9 are provided between the inner peripheral surface of the cap member H1, adjacent the inner end thereof and the adjacent outer peripheral surface of the piston rod I I5, for minimizing the escape of fluid under pressure from thecylinder 91.

The outer endof the tubular piston rod ||5 is threaded into a central opening formed in a block member |20. The block member |20 has formed in its rear vertical surface circumferentially spaced semispherical sockets which are adapted to receive the enlarged ball-shaped ends of tie rods |25, |25, and |21. The tie rods |25, |26, and |21 are held within the sockets formed in the base member |20 by means cfa cap member |28, which has ci-rcumferentially spaced openings formed therethrough, through which the central portions of the tie rods |25, |26, and |21 are adapted to extend. The inner ends of the openings in the cap member |28 are spherical `segments and are adapted to cooperate with the ball-shaped ends of the tie rods |25, |26, and |21. The cap member |28 is secured to the base member |20 by means of a plurality of circumferentially spaced bolts |29. The ends of the tie rods |25, |26, and |21, opposite the ends secured to the base member |20, are adapted to be received in circumferentially spaced semispherical sockets formed in the frame member 60. The ball-shaped ends of the tie rods |25, |26, and |21 are held within the sockets formed in' the 4frame member 60 by means of a cap member |36, which has circumferentially spaced opening formed therethrough, through which the central portions of the tie rods |25, |25, and |21 are adapted to extend. The openings in the cap member I 36, like the openings .in the cap member |28, are formed semispherically at their inner ends for cooperation vwith the associated ballshaped ends of tie rods |25, |25, and |21. The cap member |36 is mounted to the front end of the frame member 50Y by means of circumferentially spaced bolts |35. The tie rods |25, |26, and |21 are fabricated in two parts and after the reduced ends of the parts have been inserted through the openings in the cap members |28 and |36, the respective halvesare welded together. The tie rods |25, |26, and |21 permit limited relative movement to take place between the rear duct gripping unit 22 and the piston assembly 96 of the main fluid motor unit 23.

The cap member |36, which is secured to the forward end of the frame member 60 of the rear duct gripping unit 22, is provided with a pair of horizontally spaced apart openings |31 and |38 in which a pair of pipe studs |39v and |40 are disposed, respectively. The opening |38 in the cap member |36 is connected with the longitudinally extending uid passageway 66 formed in the frame member 60. The opening |31 in the cap member |36 is connected with a longitudinally extending fluid passageway |4| which is formed in the frame member 60 on the oppo.. site side thereof as the fluid passageway 66. The uid passageway |4| at its rear end opensV inwardly into the chamber 6| of the frame member 50. A pair of tubes |42 and 43 are disposed within the tubular piston rod ||5 of the main fluid motor unit 23. The tubes |42 and |43, at their one ends, are connected to the pipe studs |30 and |40, carried by the cap member |36, by means of flexible sleeve members |44 and |45 which are. fastened at their ends by means of retaining Yrings |46. From the above description, it will be observed that the tube member |43 is placed in communication with the uid pressure hose 61 by means of the flexible sleeve member |45, pipe stud |40, fluid passageway 66 in the frame member 60 of the rear duct gripping unit 22, and the fluid passageway 65 in the rear. cap member 64. The other tube member |42 has communication with the chamber 6| of the rear duct gripping unit 22 through the flexible sleeve member |44, pipe stud |39, and the fluid passageway |4| in the hub member 60 of the rear duct grippingunit 22. The other ends ofthe tubes |42 and |43 are connected to the valve block ||2 in a manner which will be described in detail hereinafter..

Mountedto the forward end of the valve block ||2 is a circular disk |50 which is secured thereto by means of a plurality of circumferentially spaced bolts |5|.v Formed integrally with the plate member |50 is a centrally located forwardly extending threaded cylindrical portion |52. Disposed over the threaded portion |52, in juxtaposition of the plate member |59, is a seal |53, preferably formed of leather. A metal expander |54 is disposed over the threaded cylinder |52 and is adapted to press the peripheral flanges of the seal |53 into contact with the adjacent peripheral walls of the cylinder 91. The sealv |53 and spring expander |54 are held in position by means of a nut |55.

A dash pot member |56 is disposed within the cylinder 91 adjacent the forward` end thereof and is provided with a striker plate |51, against which the main piston assembly is adapted to strike at the extreme end. of its forward stroke. A spring retaining member |53 is disposed within the cylinder 91 adjacent the end member |02 and is adapted to provide for thesupport of a coil spring disposed between theY member |58 and theV dash pot member |56 for normally urging it to the right. The spring |59 is adapted to cushion the shock reactions imparted to the dash pot member |56 when the piston assembly 96 strikes the latter.

A second dash pot member |50 is disposed adjacent the rear end of the cylinder 91 and is provided with a striker plate |6|, against which therear end of the piston assembly 96 is adapted to strike when in the extreme rear position. A spring |62 is disposed .betweenthe dashY pot member |68 and the cap member H1 for cushioning the shock reactions imparted to the dash pot member |69 by the piston assembly 99.

To further reduce the escape of fluid under pressure from the valve block H2, a seal is disposed about the tubular piston rod H in juxtaposition of the rear surface of the end member H4. The seal |63 is preferably formed of leather, and the lperipheral flanges thereof are maintained in contact with the adjacent peripheral walls of the cylinder 91 by means of a metal expander |64 which is held in position by means of a nut |65 threaded on the end of the tubular piston rod II5.

The valve block H2 has a pair of longitudinally extending parallel spaced apart openings or cavities |19 and |1| formed therethrough. The axis of the opening |19 lies in the vertical median plane of the valve block H2 below the horizontal median plane thereof, as shown in Figure 5. The axis of the opening |1I lies above the horizontal median .plane of the valve block H2, at one side of the vertical median plane thereof. Formed in the periphery of the opening or cavity |19 are spaced apart annular grooves |12, |13, |14, |15, and |16. A main valve member |11 is disposed within the opening and is adapted for reciprocating motion therein. A pair of spaced annular channels |18 and |19 are formed in the valve member |11, and the channels |18 and |19 each are adapted to interconnect one pair of the annular grooves formed in the :peripheral wall of the opening |19, depending on the position of the main valve |11. Formed in the peripheral wall of the opening or cavity |1| in the valve block H2 are spaced apart annular grooves ISI, |82, |83, |84, and |85. Disposed within the opening |1| is a pilot valve member |86 which is adapted for reciprocating motion therein. A pilot valve is proy is admitted to the ends of the main valve, in a 4 manner which will be fully described hereinafter.

The admission of full fluid pressure to the ends of the main valve always effects a complete shift of the latter. A pair of spaced annular channels |81 and |88 are formed in the outer periphery y2 of the valve member |86, and the channel members I 81 and |88 each are adapted to interconnect a pair of the annular grooves formed in the peripheral wall of the opening I1I, depending on the position of the pilot valve |89. By the provision of the annular grooves in the periphery of the openings |19 and |1I in the valve block I I2 and the annular channels in the valves |11 and |86, fluid circulating about the valves |11 and |86 exerts an equal pressure around the entire periphery of the valves |11 and |86, thus eliminating binding of the latter during rectilinear movement within the openings |18 and I1 I, respectively.

The tube |43 which, as explained previously, has connection at its one end with a source of fluid under pressure, is carried within the tubular piston rod I I5 and has connection at its other end with a longitudinally extending iluid passageway |99 formed in the valve block H2. The axis of the fluid passageway |98 coincides with the horizontal median plane of the valve block I I2 at one side of the vertical median plane thereof, as shown in Figure 5'. As best shown in Figure '1, the fluid passageway |98 ter- Inmates intermediate of the ends of the valve block H2. Interconnecting the fluid passageway |99 intermediate of the ends thereof and the annular groove |15 in the peripheral wall of the opening I 19 is a diagonal fluid passageway I9I lying in a plane extending transversely of the valve block H2. Interconnecting the fluid passageway |99, adjacent the inner end thereof, and the annular groove |83 in the peripheral wall of the opening I1I is a diagonal fluid passageway |92 lying in a plane parallel to the fluid passagewat7 I9I.

The tube H12, which, as explained previously, has connection at its one end to the chamber 6I of the rear duct gripping unit 22, is carried within the tubular piston rod H5 parallel to tube |43 and has connection at its other end with a longitudinally extending fluid passageway |93 formed in the valve block H2. The axis of the fluid passageway |93 lies in the horizontal median plane of the valve block H2 on the opposite side of the vertical median plane thereof as the fluid passageway |99. As best shown in Figure 9, the fluid passageway |93 extends through the valve block H2. Interconnecting the fluid passageway |93 and the annular groove |16 in the peripheral wall of the opening |18, as shown in Figure l1, is a diagonal iluid passageway |95 lying in a plane extending transversely of the valve block H2. The fluid passageway |93 is also interconnected with the annular groove |12 in the peripheral wall 0f opening |19, as shown in Figure 12, by a diagonal fluid passageway |96 lying in a plane parallel to the fluid passageway |95. As shown in Figure 10, a channel |94 having connection with fluid passageway |93 is formed in the end of the valve block H2. The channel |96 has connection at its outer end with a mating channel |91 formed in the plate member |59, as shown in Figure 19, which channel |91 connects with a passageway |98 opening into the cylinder 91 at the forward end of the piston assembly 96.

A longitudinally extending fluid passageway 299 is formed in the valve block H2. The uid passageway 299 opens at its outer end into the tubular piston rod H5. The axis of the fluid passageway-209 lies in the vertical median plane of the valve block H2 above the horizontal median plane thereof. Interconnecting the fluid passageway 299 and the annular groove |13 in the peripheral wall of the opening |19, as best shown in Figures 13 and 14, is a diagonal fluid passageway 29| lying in a transverse plane of the valve block I I2. Interconnecting-the fluid passageway 299 adjacent its one end and the annular groove IBI in the peripheral wall of the opening I1I is a diagonal fluid passageway 292, which lies in a transverse plane parallel to the fluid passageway 29|. The iluid passageway 289 is also connected with the annular groove in the peripheral wall of the opening |1| by means of a fluid passageway 293, which lies in a transverse plane parallel to the fluid passageways 28| and 282.

A pair of coaxially aligned longitudinally extending fluid passageways 294 and 285 are formed inwardly of the opposite ends of the valve block H2 below the horizontal median plane thereof, and to one side of the vertical median plane, as shown in Figure 5. Fluid passageway 284 at its inner end is connected to the annular groove |82 in the peripheral wall of the opening |1| by means of a diagonal fluid passageway 296 which lies in a transverse plane of the valve block H2, as' shown inFigures 14 and 16. Fluid passageway 205 at its inner end is connected to the annular groove |84 in the peripheral wall of the' opening |1| by means of a diagonal iluid passageway 201 which lies in a transverse plane parallel to thefluid passageway 206, as shown in Figures 16 and 18.

The iluid passageway 204 at its outer end connects with the adjacent end of opening throughv a shallow key hole shaped channel 203 formed in theplate member |50, as shown in Figures 19 and 20. The fluid passageway 205 at itsr outer end connects with the adjacent end ofopening |10 through a shallow key hole shaped channel 209 formed in the end block H4, as shown in Figures 21 and 22.

A longitudinally extending fluid passageway 2| is formed in the valve block I I2 and the axis oflthe'passageway lies below the horizontal medianA plane of valve block ||2 on the opposite side of the vertical median plane as the fluid pa'ssageways 204 andy 205, as shown in Figure 5. As best shown in Figure 24, the iiuid passageway 2'|| terminates intermediately of the ends of' the valve block ||2 and is connected at its inner end to the annular-groove |14 in the peripheral wall Vof the opening |10 by a diagonal fluid passageway 2|2 which lies in a transverse plane of the valveblock ||2. The outer end of the iluid passageway 2| I connects with an opening 2|'3, formed in the end block ||4, seal |63, and spring retainer |64, which communicates with the cylinder 91 at the rear of the piston assembly 96. l

The pilot valve |86 is provided with reduced end' portions` 2| Band 211. The end 2|6 extends through the opening 2|8 formed in the plate member seal |53, and spring retainer |54, andis adapted to engage the face plate |51 of the dash pot member |56 when the piston as-` sembly 96 is at the extreme end of its forward stroke within the cylinder 91. The end 2|1 extends through the opening 2|9 in the end block ||,4, seal |63, and spring retainer |64, and is adapted to engage the striker plate |6| of the dash pot member |60 when the piston assembly 96 is at the extreme end of its rearward stroke within the cylinder 91.

Themain valve |11 is provided with reduced endportions 220 and 22| which are adapted to engage the enlarged ends of the key hole chan- 'nels 208 and 209 in the members |50 and H4,

respectively. The reduced end portions 220 and 22| are, providedv in, order that fluid under pressure may be directed to the ends ofthe main,

valve |11 yfor shifting the latter rectilinearly.

ReferringV now to `Figures 1, la, 2, 2a, 25,.and 26,

we shall describe the operation of the duct rodding machine of our present invention. After the duct rrodding machine has been .placed within a duct or conduit, fluid under pressure isadmitted to the fluid passageway. in the rear capmernber 6'4 of the rear duct gripping unit` 22 through the hose line 61,. The uid under pressure then ilows through the iiuid passageway 65 in the cap mem-y ber 64to the longitudinally extending fluid passageway 66 formed in the frame member 66 of therear duct gripping unit y22. The fluid continues from the passageway 66 to the opening |38 in thefrontcap member |36 ofthe rear duct gripping unit 22. From the opening |39 the uid passes .through pipe stud |40, .ilexible;sleeve.mem ber |41, and hence throughfthetube-MS carried kinthe-tubular piston 'rod' 1| 5 to theA fluid passage- Following theschematlc diagram shownin Figure 25, it will be observedthat with the valve |86 in the position shown, the iiuid passageways |92 and 201 are placed in communication by means of the channel |83 in the pilot valve |86, thus permitting the Huid under pressure to flow from inlet fluid passageway |90, through passageway |92, channel |88, passageway 201, passageway 205, channel 269 to the end of the main valve |11. When the main valve |11 is positioned to the left, iluid passageways |9| and 2 |2 are placedk into communication by means of channel |19 in the main valve |11, thus allowing the fluid under pressure to flow from the passageway |90 through the passageway |9|, channel |19, passageway 2|2, and passageway 2|| into the main cylinder 91 at the rear of the main piston assembly 96 of the main iluid motor unit 20. The fluid entering the cylinder 91 exerts a force on the rear end of the piston assembly 96 and the assembly 96 is pushed forward within the cylinder 91. Carried forward with the piston assembly 96 is the tubular piston rod |5 and the rear duct gripping unit 22 flexibly mounted to the rear end of the latter.

Fluid entering the cylinder 91 is also transmitted to the longitudinally extending fluid passageway |0| formed along the outer periphery of the cylinder 91, as shown in Figures 3 and 4. From the passageway |0| the fluid flows through passageway |03 in the end member |02 at the forward end of cylinder 91, pipe stud |01, flexible sleeve member |09, pipe stud |08, opening 34 in the plug member 21, and hence into the cylinder 26 of the front duct gripping unit 2|. The fluid entering theV cylinder 26 urges the piston assembly 39, together with the piston rod 38, to the left, thereby extending the cam member 45 into duct gripping position.

Also, while the pilot valve |66 is in the position shown in Figure 25, the channel |81 formed therein interconnects the huid passageways 202 and 206 and iluid is bled from the other end of the main valve |11 through channel 208 in the plate member |59, passageways 204 and 206, channel |81, passageway 262, and passageway 200. From the passageway 200 the iluid is discharged into one end of the tubular piston rod ||5 which, at its other end, is open to the atmosphere. Simultaneously, the chamber 6| of the rear duct gripping unit 22 is bled by placing it in communication with the exhaust passageway 200 through the longitudinal fluid passageway |0| formed in the frame member 60, opening |31 in the front cap member |36, pipe stud |39, ilexible sleeve member |44, tube |42 carried in the tubular piston rod I5, and the fluid passageway |93 inthe valve block ||2. The fluid passageway |93 communi- Cates with passageway |96 which is connected to the passageway 20| through the channel |18 of the main valve |11. The passageway 20| is connected with the exhaust passageway 200 which, as described previously, opens into the tubular piston rod ||5 and hence into the atmosphere.

When the chamber 6| in the rear duct gripping unit 22 is bled, the spring 80 urges the piston assembly 15 to the right, thereby maintaining the cam member 8| in its retracted position. It will be observed that while the chamber 6| is being bled through fluid passageway |93, the front end of the main cylinder 91 is also being bled as the one end of the fluid passageway |93. opens into the forward end ofvoylinder 91.

The operationsof bleeding the forwardend of main cylinder 91 and chamber 6| in the rear duct gripping unit 22, and admitting fluid under presscribed hereinbeiore.

15 sure to the forward duct gripping unit 2| and the rear end of the main cylinder 91, takes place substantially simultaneously. Y

When the main piston assembly 9S reaches the extremity of its forward stroke within the main cylinder 91, the reduced end 215 of the pilot Valve |85 strikes the face plate |51 of the dash pot member |56 and the pilot valve |86 is shifted to the right, from the position shown in Figure 25 to the position shown in Figure 26. With the pilot valve |86 in this position, fluid is bled from the right end of the opening |10 through channel 299 in the end block IIl, fluid passageways 205 and 201, channel |88 in the pilot valve |86, fluid passageway 203, and fluid passageway 2,00 which, as mentioned before, opens into the tubular piston rod I I5.

Simultaneously, while the right end of opening |10 is bled, fluid under pressure is directed into the left end of opening |19, thereby shifting the main valve |11 to the right to the position shown in Figure 26. Fluid under pressure is transmitted to the left end of opening |10 from the passageway |90 by means of passageway I92, channel |81 in the pilot valve |89, passageways 206 and 204, and channel 208 formed in the end member |59. The passageway |90, as described above, is connected with a source of fluid under pressure through tube HIS in the tubular piston rod H5, flexible sleeve Ifl, pipe stud i559, opening |38 in the front cap member |35 of the rear duct gripping unit 22, longitudinal fluid passageway 66 in the frame member 60, passageway 9:1 in the rear cap member Sil, and the inlet hose With the main valve |11 shifted t0 the right, the fluid is bled from the cylinder 28 of the front duct gripping unit 2| through opening 39 in the plug 21, pipe stud |08, flexible sleeve 199, pipe stud |01, passageway |63 in the end member |02, and the longitudinally extending passageway |I of the main cylinder 91. The fluid is further bled from the passageway IGI and the rear end of the main cylinder 91 by means of the fluid passageways 2|I and 2I2, channel |18 in the main valve |11, passageway 20I, and passageway 290. The passageway 200, as aforedescribed, discharges into the tubular piston rod I I to the atmosphere.

While fluid is bled from the cylinder 26 of the front duct gripping unit 2i, so as to permit the spring 44 to urge the piston assembly 39 to the right, thereby releasing the cam member |55 from duct gripping engagement, fluid under pressure is admitted to the chamber of the rear duct gripping unit 22 for forcing the piston assembly and piston rod 1d to the left, as viewed in Figures 1, la, 2, and 2a, for disposing the cam member 8| into duct gripping engagement. Fluid under pressure is transmitted to the fluid passageway |90 in the valve block I|2 from the fluid hose 61 in a manner which has been fully de- From the passageway 599 the fluid is directed to the chamber 5I of the rear duct gripping unit 22 through passageway I9I, channel |19 in the main valve |11, passageways |95 and |93, tube |43 in the tubular piston rod I I5, flexible sleeve |44, pipe stud |39, opening |31 in the front cap member |36 of the rear duct gripping unit 22, and the longitudinally extending fluid passageway I4I in the frame member 60.

The fluid passageway |93 at its other end opens into the forward end of the main cylinder 91 and thus admits fluid under pressure therein when the main valve |11 is disposed at the right end ofthe opening |10 in the valve block I I2.

Y Since the main piston assembly 96 is held stationary by means of the rear duct gripping unit 22, whose cam member 8| is in duct gripping engagement, the fluid under pressure admitted to the forward end of the main cylinder 91 forces the cylinder 91 and the forward duct gripping unit 2| to the left, as viewed in Figures 1, la, 2, and 2a. When the rear end of the cylinder 91 nears the rear end of the main piston assembly 95, the reduced end 2I1 of the pilot valve |86 engages the striker plate ISI of the dash pot member |60 and the valve |35 is shifted to the left to the position shown in Figure 25. This effects shifting of the main valve |11 also to the left, to the position shown in Figure 25, which places the chamber 5I of the rear duct gripping unit 22 and the front end of main cylinder 91 under bleed while causing a flow of fluid under pressure to the cylinder 26 of the front duct gripping unit 2| and the rear end of the main cylinder 91.

From the foregoing description, it will be realized that the duct rodding machine of our invention literally crawls inside of a duct or conduit. That is to say, while the main cylinder 91 is held stationary by means of the front duct gripping unit 2 I, the main piston assembly 96 and the rear duct gripping unit 22 are advanced forwardly. Upon the main piston assembly 96 reaching the end of its forward stroke, the main piston assembly 95 is held stationary by means of the rear duct gripping unit 22 and the main cylinder 91, and front duct gripping unit 2| are advanced forwardly. These cycles repeat themselves at approximately the rate of cycles per minute, as long as fluid under pressure'is supplied to the fluid hose 01.

Although it may appear from the above description of the construction and operation of the device of our present invention that it is very complicated, it is, on the contrary, a simple device of economical construction and one which is very effective in rodding a duct.

While we have shown and described what we believe to be a preferred embodiment of our present invention, it will be understood that various arrangements and modifications may be made therein without departing from the spirit and scope of our invention.

We claim: Y

1. A laterally flexible duct rodding machine, comprising a main fluid pressure operated reciprocating motor having two relatively movable parts, a pair of auxiliary pressure actuated means, one flexibly connected to each of said main motor parts whereby the longitudinal axes of said auxiliary pressure actuated means are free to move out of coincidence with the longitudinal axis of said main motor, and expansible duct gripping means actuated by said auxiliary pressure actuated means for gripping a duct at one end of the device when the main motor advances the other end of the device.

2. In a device of the class described, the combination of a main fluid pressure operated reciprocating motor having two relatively movable parts, a pair of duct gripping units one connected to each of said main motor parts, said duct gripping units each having expansible duct gripping means, auxiliary pressure actuated means for alternately expanding one of said duct gripping means while simultaneously retracting the other of said duct gripping means, and automatic valve means unitary with one of said main motor parts for controlling fluid pressure to said main motor and said auxiliary pressure actuated means.

3. A laterally flexible duct rodding machine, comprising a main fluid pressure operated rervpiston,

17 ciprocating motor having two relatively movable parts, a pair of auxiliary pressure actuated motors, each flexibly connected to one of said main motor parts whereby the longitudinal laxes of said auxiliary pressure actuated motors are free to move out of coincidence with the longitudinal axis of said main motor, expansible duct gripping means actuated by the auxiliary motors for gripping a duct at one end of the device when the main motor advances the other end of the device, and automatic valve means unitary with one of said main motor parts for controlling fluid pressure to said main and auxiliary motors.

4.-. In a laterally flexible `duct redding machine, the combination of a main fluid pressure operated reciprocating motor comprising` a double ended cylinder and a piston ltherein adapted to be reciprocated in said cylinder, a pair of auxiliary pressure actuated motors, one`V flexibly connected to said cylinder andthe other flexibly connected to saidpiston whereby thelongitudinal axes of saidauxiliary pressure actuated motors are free to move out of coincidence with the longitudinal axis of said main motor, automatic valve means disposed within'said piston for controlling fluidpressure to said vmainand auxiliary motors, and expansible duct gripping means actuated by' lthe -auxiliary motors for gripping a duct at one end of the device when the main motor advances'the other end of the device. v

A5. In a device of the class described, the combination oi a main fluid pressureV operatedreciprocating motor comprising a double ended main cylinder and a'piston therein adapted 'to be reciprocated in said cylinder, a pair of auxiliary pressure actuated motors disposed adjacent opposite ends of said main motor, one connected to said cylinder and the other'connected to said expansible duct grippingl means each actuated alternately by the auxiliary `motors, automatic valve means for controlling lfluid pressure to said main and auxiliary motors, `said valve means comprising a valvey carried in said piston and adapted to be disposed in 'one of n two positions, a rst fluid passageway between said valve and one of said auxiliary motorsv and one end of said cylinder, a'second iluid passageway between said valve and the other of vsaid auxiliary motors and the other end of said ,cylinder, a fluid inlet terminating in' said piston, said valve in the first Aposition permitting iiuid ow between said inlet and said first passageway and in the second position permitting fluid ilow between said inlet and said second passageway, and means carried within said pistonfor controlling movement of said valve between said first and second positions.

6. In a device of thev class described, the combination of a main iluid pressure operated reciprocating motor comprising a double ended main cylinder and a piston therein adapted to be reciprocated in said cylinder, a pair of auxiliary pressure actuated motors disposed adjacent opposite ends oi said main motor, one connected to said cylinder and the other connected to said piston, expansible duct gripping means each actuated alternately by the auxiliary motors, automatic valve means for controlling fluid pressure to said main and auxiliary motors, said valve means vcomprising a rectilinearly movable valve carried in saidv piston ,and adapted4 to be disposed in one of two positions, a first fluid passageway between said valve ,and oneof said auxiliary motors and one end of vsaid cylinder,

18 a second fluid passageway between said valve and the other oi said auxiliary motors and the other end of said cylinder, a fluid inlet terminating in said'piston, saidvalve in the first position Ypermitting fluid flow between said inlet and said first passageway and in the second posi- `tion permitting fluid flow between said inlet and said second passageway, and means carrsi'ed within said piston for controlling movement 'of said valve between said first and second positions.

`7. lIn a `device of the class described, the combination of a main fluid pressure operated reciprocating motor comprising a double ended main cylinder land a piston therein adapted to be recip- Vrocated in said cylinder, a pair of auxiliary presvalve andthe other of said auxiliary motors and the other end of said cylinder, a fluid inlet terminating in said piston, said valve in the first position permitting iluid ilow between said inlet and lsaid first passageway and in the second position permitting fluid ow between said inlet and said second passageway, a second cylindrical cavity within said piston, a rectilinearly movable pilot valve in said cavity, said pilot valve having `reduced end portions adapted to protrude outwardly through the ends of said piston, whereby said pilot valve is shifted when the reduced end portions thereof contact the adjacent ends of the main cylinder when said piston reciprocates in the latter, and said pilot valve having fluid connection with said rst named valve for controlling movement thereof between said first and second positions.

, 8. In a laterally iiexibleduct redding machine, the combination of a main fluid pressure operated reciprocating motor comprising a double 'ended cylinder and a'piston therein adapted to be reciprocated in said cylinder, shock absorbing means in said cylinder'adjacent each end thereof for absorbing the momentum of said piston when the latter is reciprocating, a pair of auxiliary pressure actuated motors, one ilexibly connected to said cylinder and the other ilexibly connected to said piston, automatic valve means disposed within said piston for controlling uid pressure to said main and auxiliary motors, and expansible duct gripping means actuated by the auxiliary motors for gripping a duct at one end of the device when the main motor advances the other end of the device.

9. In the device of `the class described, the combination'of a main fluid pressure operated reciprocating motor having two relatively movable parts, a `pair of duct gripping units one connected to each of said main motor parts, said duct gripping units each having expansible duct gripping means comprising an extensible cam, and auxiliary pressure actuated means for alternately extending each of said cams.

10. In adevice of the class'described, the combination of a main fluid pressure operated 'reciprocating motor having two relatively movable parts, a pair of duct gripping units one connected to each of said main motor parts, said duct gripping units each having expansible duct gripping means comprising an extensible cam, a pair of spaced lost motion connectionsfor pivotally mounting each of said cams to said duct gripping units, and auxiliary pressure actuated means for alternately extending each of said cams.

11. In a device of the class described, the combination of a main fluid pressure operated reciprocating motor having two relatively movable parts, a pair of duct gripping units one connected to each of said main motor parts, said duct gripping units each having expansible duct gripping means comprising an extensible cam, auxiliary pressure actuated means for alternately extending each of said cams, and automatic valve means unitary with one of said main motor parts for controlling fluid pressure to said main motor and said auxiliary pressure actuated means.

12. In a device of the class described, the combination of a main fluid pressure operated reciprocating motor having two relatively movable parts, a pair of duct gripping units one connected to each of said main motor parts, said duct gripping units each having expansible duct gripping means comprising an extensible cam, a pair of spaced lost motion connections for pivotally mounting each of said cams to said duct gripping units, auxiliary pressure actuated means for alternately extending each of said cams and automatic valve means unitary with one of said main motor parts for controlling fluid pressure to said main motor and said auxiliary pressure actuated means.

13. In a laterally flexible duct rodding machine, the combination of a main fluid pressure operated reciprocating motor comprising a double ended main cylinder and a main piston therein adapted to be reciprocated in said cylinder, a pair of duct gripping units each having an auxiliary pressure actuated motor comprising a piston and cylinder, the cylinder of one of said auxiliary motors being flexibly connected to said main cylinder and the cylinder of the other of said auxiliary motors being flexibly connected to said main piston, said duct gripping units each having duct gripping means comprising an extensible cam, a first lost motion connection for pivotally mounting one each of said cams to each of said cylinders of said auxiliary motors, a second lost motion connection for pivotally mounting one each of said cams to each of said pistons of said auxiliary motors, said cams adapted to be extended alternately by said auxiliary motors, and automatic valve means for controlling fluid pressure to said main and auxiliary motors.

14. In a laterally flexible duct rodding machine, the combination of a main fluid pressure operated reciprocating motor comprising a double ended main cylinder and a main piston therein adapted to be reciprocated in said cylinder, a pair of duct gripping units each having an auxiliary pressure actuated motor comprising a piston and cylinder, the cylinder of one of said auxiliary motors being flexibly connected to said main cylinder and the cylinder of the other of said auxiliary motors being flexibly connected to said main piston, said duct gripping units each having duct gripping means comprising an extensible cam, a lost motion connection for pivotally mounting each of said cams to each of said cylinders of said auxiliary motors, a second lost motion connection for pivotally mounting one each of said cams to each of said pistons of said auxiliary motors, said cams adapted to be extended alternately by said auxiliary motors, automatic valve means for controlling fluid pressure to said main and auxiliary motors, said valve means comprising a first cylindrical cavity within said piston, a rectilinearly movable valve in said cavity and adapted to be disposed in one of two positions, a first fluid passageway between said valve and one of said auxiliary motors and one end of said cylinder, a second fluid passageway between said valve and the other of said auxiliary motors and the other end of said cylinder, a fluid inlet terminating in said piston, said valve in the first position permitting fluid flow between said inlet and said first passageway and in the second position permitting fluid flow between said inlet and said second passageway, a second cylindrical cavity within said piston, a rectilinearly movable pilot valve in said cavity, said pilot valve having reduced end portions adapted to protrude outwardly through the ends of said piston, whereby said pilot valve is shifted when the reduced end portions thereof contact the adjacent ends of the main cylinder when said piston reciprocates in the latter, and said pilot valve having fluid connection with said first named valve for controlling movement thereof between said first and second positions.

15. In a valve block having a first and second cavity therein, an inlet fluid passageway in communication with said first and second cavities, a first outlet fluid passageway in communication with said first and second cavities, a second outlet fluid passageway in communication with said second cavity, a third outlet fluid passageway in communication with said second cavity, a first fluid passageway between the intermediate portion of said first cavity and the one end of said second cavity, a second fluid passageway between the intermediate portion of said first cavity and the other end of said second cavityy a first valve disposed in said first cavity and adapted to be located in one of two positions, said first valve in the first position interconnecting said inlet fluid passageway with said second fluid passageway and said first fluid passageway with said first outlet fluid passageway, said first valve in the second position interconnecting said inlet fluid passageway with said first fluid passageway and said second fluid passageway with said first outlet fluid passageway, a second valve disposed in said second cavity and adapted to be located in one of two positions, said second valve in the first position interconnecting said inlet fluid passageway with said third outlet fluid passageway and said second outlet fluid passageway with said first outlet fluid passageway, and said second valve in the second position interconnecting said inlet fluid .passageway with said second outlet fluid passageway and said third outlet fluid passageway with said first outlet fluid passageway.

16. In a valve block, a first and second cavity therein, a plurality of spaced apart grooves in the periphery of said first cavity, a plurality of spaced apart grooves in the periphery of said second cavity, an inlet fluid passageway in communication with one of said grooves in each of said first and second cavities, a first outlet fluid passageway in communication with one of said grooves in each of said first and second cavities. a second outlet fluid passageway in communication with one of said grooves in said second cavity, a third outlet fluid passageway in communication with one of said grooves in said second cavity, a first fluid passageway between one of said grooves in said first cavity and the one end of said second cavity, a second fluid passagewayl between one of said grooves in said first cavity and the other end of said second cavity, a rst valve disposed in said first cavity and adapted to be located in one of two positions, said first valve in the first position interconnecting thegrooves to which said inlet fluid passageway and said second fluid passageway communicate and interconnecting the grooves to which said rst fluid passageway and said first outlet fiuid passageway communicate, said first valve in the second position interconnecting the grooves to which said inlet fluid passageway and said first fluid passageway communicate and interconnecting the grooves to which said second fluid passageway and said first outlet fluid passageway communicate, a second valve disposed in said second cavity and adapted to be located in one of two positions, said second valve in the first position interconnecting the grooves to which said inlet fluid passageway and said third outlet fluid passageway communicate and interconnecting the grooves to which said second outlet fluid passageway and said rst outlet fluid passageway communicate, and said second valve in the second .position interconnecting the grooves to which said inlet fluid passageway and said second outlet iiuid passageway communicate and interconnecting Ithe grooves to| which said third outlet fluid passageway and said first outlet fiuid passageway communicate.

17. In a valve block, a first and second cavity therein; first, second, third, fourth, and fifth spaced apart grooves formed in the periphery of said first cavity; first, second, fourth, and fifth spaced apart grooves formed in the periphery of said second cavity; an inlet fluid passageway in communication with said third groove in said first outlet fluid passageway in communication with said first and fifth grooves in said first cavity and said second groove in said second cavity, a second outlet fluid passageway in communication with said first and fifth grooves in said second cavity, a third outlet fluid passageway in communication with said third groove in said second cavity, a first fluid passageway between said second groove in said first cavity and the one end of said second cavity, a second fluid passageway between said fourth groove in said first cavity and the other end of said second cavity, a first valve disposed in said first cavity and adapted to be located in one of two positions, said first valve in the first position interconnecting said first and second grooves and interconnecting said third and fourth grooves, said first valve in the second position interconnecting said second and third grooves and interconnecting said fourth and fifth grooves, a second valve disposed in said second cavity and adapted to be located in one of two positions, said second valve in the first position interconnecting said first and second grooves and interconnecting said third and fourth grooves, and said second valve in the second position interconnecting said second and third grooves and interconnecting said fourth and fifth grooves.

18. In a valve assembly comprising a valve and first and second end members, a first cylindrical cavity extending longitudinally within said valve block on an axis lying above the horizontal median plane of the latter at one side of the vertical median plane thereof, a second cylindrical cavity extending longitudinally within said valve block on an axis lying in the vertical median plane of the latter below the horizonta1 median `plane thereof; first, second, third, fourth, and

Afifthspaced apart annular grooves formed in the periphery of said first cavity; first, second, third, fourth, and fifth spaced apart annular grooves formed in the periphery of said second cavity; an inlet fluid passageway extending longitudinally within said valve block on an axis lying in the horizontal median plane of the latter on the saine side of the vertical median plane thereof as the first cylindrical cavity, a first diagonal fluidlpassageway in a transverse plane of said valve block for interconnecting said inlet fluid passageway and said 'fourth annular groove in said second cavity, a second diagonal fluid passageway parallel to said first diagonal fluid passageway for interconnecting said inlet fluid passageway and said third annular groove in said first cavity, a first outlet fluid passageway extending longitudinally on an axis lying in the vertical median plane of said valve block above the horizontal median plane thereof, a third diagonal fluid passageway in a transverse plane of said valve block interconnecting said first outlet fluid passageway and said first annular groove of said first cavity, a fourth diagonal fluid passageway parallel to said third diagonal fluid passageway for interconnecting said first outlet fluid passageway and said fifth annular groove in said first cavity, a fifth diagonal fluid passageway parallel to said third and fourth diagonal fluid passageways for interconnecting said first outlet fluid passageway and said second annular groove in said second cavity, a second outlet fluid passageway extending longitudinally on an axis lying in the horizontal median plane of the valve block on the opposite side of the vertical median plane as said first cavity, a sixth diagona1 fluid passageway parallel to said fifth diagona1 fluid passageway for interconnecting said second outlet fluid passageway and said first annular groove in said second cavity, a seventh diagonal fiuid passageway parallel to said sixth diagonal fluid passageway for interconnecting said second outlet fluid passageway and said fifth annular groove in said second cavity, a third outlet fluid passageway extending longitudinally on an axis lying below the horizontal median plane of the valve block on the same side of the vertical median plane thereof as said second outlet fluid passageway, an eighth diagonal fiuid passageway parallel to said seventh diagona1 fluid passageway for interconnecting said third outlet fluid passageway and said third annular groove in said second cavity, first and second coaxially aligned intermediate fluid passageways opening into the opposite ends of said valve block on an axis lying below the horizontal median plane of the latter on the same side of the vertical median plane thereof as said first cavity, a ninth diagonal fluid passageway parallel to said eighth diagonal fluid passageway for interconnecting said first intermediate fluid passageway and said second annular groove in said first cavity, a tenth diagonal fluid passageway parallel to said ninth diagonal fiuid passageway for interconnecting said second intermediate fluid passageway and said fourth annular groove in said first cavity, a first channel in said first end member for interconnecting said first intermediate fluid passageway and the one end of said second cavity, a second channel in said second end member for interconnecting said second in`` termediate fluid passageway and the other end of said second cavity, a first valve disposed in said first cavity and adapted to be located in one of two positions, said first valve in the first position interconnecting said first and second grooves and interconnecting said third and fourth grooves, said first valve in the second position interconnecting said second and third grooves and interconnectingsaid fourth and fifth grooves, a second valve disposed in said second cavity and adapted to be located in one of two positions, said second valve in the rst position interconnecting said rst and second grooves and nterconnecting said third and fourth grooves, and said second valve in the second position interconnecting said second and third grooves and interconnecting said fourth and fth grooves.

CRONJE JASPER.

GEORGE T. HAWK.

24 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

